Validate types implement interfaces

[bhavinshah7]

Add a schema validation rule ensuring object and interface types have all the fields that they need to implement the interfaces they say they implement.

//Object
ObjectTypeDefinition : desc=StringValue? 'type' name=Name implementsInterfaces=ImplementsInterfaces? directives+=Directive* ('{' fieldDefinition+=FieldDefinition* '}')?;
ObjectTypeExtensionDefinition:'extend' 'type' name=Name implementsInterfaces=ImplementsInterfaces? directives+=Directive* ('{' fieldDefinition+=FieldDefinition* '}')? ;

//Interface
InterfaceTypeDefinition : desc=StringValue? 'interface' name=Name implementsInterfaces=ImplementsInterfaces? directives+=Directive* ('{' fieldDefinition+=FieldDefinition* '}')?;

InterfaceTypeExtensionDefinition: 'extend' 'interface' name=Name implementsInterfaces=ImplementsInterfaces? directives+=Directive* ('{' fieldDefinition+=FieldDefinition* '}')?;

Other validations for reference

Add to an existing validation class or link a new validation here

similar validation in graphql-java

[KshitijSharma745]

Hey @bhavinshah7, I would like to work on this. Can you please assign this to me?